Polarization-balanced beamsplitter

Abstract

A beamsplitter assembly that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting.

What is claimed is: 
     
       1. A polarization-balanced beamsplitter assembly for providing six polarization-balanced output beams from a single input light beam independent of the polarization state of the input light beam, wherein any polarization in said input beam is resolvable along an s-component axis and a p-component axis, wherein said s-component axis defines an s-component polarization and said p-component axis defines a p-component polarization, wherein said s-component axis is orthogonal to said p-component axis, the assembly comprising: thirteen beamsplitter cubes arranged to provide said six polarization-balanced output beams, each cube containing a partially reflective surface, wherein a light beam incident on said partially reflective surface is split into a transmitted light beam and a reflected light beam, wherein said transmitted light beam contains a first portion of said s-component polarization and a first portion of said p-component polarization, wherein said reflected light beam contains a second portion of said s-component polarization and a second portion of said p-component polarization, wherein   each cube contains a plane of incidence defined by the incident light beam and the reflected light beam,   wherein each of said six polarization-balanced output beams pass through two pairs of polarization-balanced beamsplitter cubes selected from said thirteen beamsplitter cubes, wherein each of said pairs of polarization-balanced beamsplitter cubes have orthogonal planes of incidence relative to the incident light beam, and wherein a light beam passing through each of said pairs of polarization-balanced beamsplitter cubes is either transmitted by both polarization-balanced beamsplitter cubes or reflected by both polarization-balanced beam splitter cubes.   
     
     
       2. The beamsplitter assembly as recited in claim 1, wherein said beamsplitter cubes are 50 percent beamsplitter cubes. 
     
     
       3. The beamsplitter assembly as recited in claim 1, wherein said six polarization-balanced output beams are of equal intensity.